Sectioning Large Heavily Sclerotized Whole Insects

Abstract

THE following account shows how to obtain much-improved sections of large heavily sclerotized whole insects. The method should be applicable to many other kinds of animals which present similar problems. Use is made of a fixing, dehydrating, and clearing agent, tetrahydrofuran, which produces a minimum of tissue hardening. It is highly volatile thus permitting rapid removal in the paraffin oven, dissolves paraffin and celloidin. Tetrahydrofuran (furan) has been used by other workers with good results^1,2,3. Paraffin infiltration is done in a partial vacuum. The blocks may be soaked 24 hr. or longer in either ‘Mollifex’ (B.D.H.) or in water (preferably with a small amount of detergent) or in 75 per cent alcohol. Before sectioning, the blocks in the soaking medium, if such is used, are cooled to approximately 15°C. Better than average sections are obtained.